Laminated wall board



Feb. 9, 1932. P. w. CODWIISE 1,843,915

LAMINATED WALL BOARD Filed. Feb. 25; 1928 ATTORNEYS Patented Feb. 9, 1932 UNi ED STATES ATENT OFFICE PHILIP W. CODWISE, OF KENMORE, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, '.I.O

CERTAIN-[DEED PRODUCTS CORPORATION, A CORPORATION OF MARYLAND LAMINATED WALL BOARD Application filed February 23, 1928. Serial No. 256,091.

The present invention relates to wall boards and has for its object the production of a thick laminated board composed for the most part of wood fiber, and having such strength, toughness and freedom from warpage and having such good insulating qualities, that it can be usedwith advantage as a plaster base on which to apply stucco and a hard finish.

' This new product is obtained by a novel process. Other objects and advantages of the present invention will become clear from the following description taken in conjunction with the accompanying drawings wherein v ' Fig. 1 is a diagrammatic representation of one of the layers out of which the board is built, the plies of that layer being separated in the drawings to show their relation one to the other;

Fig. 2 is a perspective view of a fragment of the complete board.

The complete board, as illustrated in Fig.

2, comprises several separate layers, prefer-o- 5" paper making operations. Such screenings consist largely of slivers, shives or bundles of fibers not torn apart when the spruce log is ground to .pulp on the grind stone.

I find there is much advantagein using screenings of this character as the major constituent and preferably the only fibrous component of the two outermost plies of each layer, for the layer is thereby given anap or roughened surface of very substantial advantage when the layers are being cemented together by an adhesive which may thereby bond to the rough surface and interlock with thelong fibers thereof. This rough layer is also of great importance in securing a firm bond between the board anda layer of plaster .hollander.

fibered stock is important, and I prefer to spread thereon when the board is put into use as the inner wall of the building.

I find that there is advantage in having the four outermost plies for each layer composed essentially of such screenings, or other long fibred stock, for instance, sawdust or ground peanut shells, because of the toughness and strength inherent in a layer of stock built up out of slivers, shives and bundles of fibers.

The two innermost plies 5 and 6 of each layer can well containa relatively high percentage of short fibered stock.

Other details of the product will become clear fromthe followingdetailed description of the process by which it is made. The

short fibered stock, for the inner plies 5 and 6, is made by charging paper waste and water into a hollander heater and there beating on a continuous plan until a smooth uniform pulp is produced. Newspaper waste, container board waste, and the like, can be used, and to these waste materials I prefer to add in the beater 25% of ground wood stock, preferably spruce, and up to 10% of ground spruce screenings, all by dry weight. Rough- 1y estimated, it takes about threequarters of an hour to pass such a charge through the A suitable sizing of the short effect this sizing with an alum rosin size, introducing the alum to the extent of 4% by dry weight into'thebatch while in the hollander, and introducing the solution of rosin at the head box just before the stock passes to the jordan, using rosin to the extent of 3% by dry weight.

From the hollander beater the short fibered stock passes to a beater chest, then to the jordan, then to the machine chest and then to two of the cylinders of a six-cylinder machine as hereinafter described. Each of.

these plies hasa thickness of about .011". This short fibered stock thus sized ispressed as it. leaves, these two cylinders for felting between the four outer plies of long fibered stock.

The four outside or long fibered plies are preferably made as follows: Wood pulp screenings preferably ground .spruce with as many shives, slivers and bundles of fibers short fibered stock. Then the charge is li htly jordaned and then passed to four cy in er s of the six-cylinder machine. If desired, 15% to 35% of veneer sawdust, or ground peanut shells, can be added to the stock while in the beater. This gives a greater bulk without reducing the tensile strength of the finished product.

When the two inner plies and the four outer plies are delivered from the six cylinders of the cylinder machine each is pressed sufiiciently to bond the constituents and to remove excess water and the entire group of six are passed through pressure rollswhich squeeze and felt the plies together into a coherent sheet or layer. The shives and slivers of the four outer plies materially contribute to this knitting together of the six plies into a single layer. The layer is dried on drums in usual manner but withoutsuch calendering or other surface treatment as would de= stroy the'roughened or napped surface of the outermost plies. This-material has good heat insulating power-because of the large number of air cells between the felted bun- .dles of fibers.

At this sta e of the process a layer comprising six plies of stock weighs about 2.2 oz. per square foot and carries about 4% of water. Each layer has a thickness of about .065 and can be rolled up for storage or transportation.

The next step in the process consists'in passing five or more of these layers through a laminating machine and there applying a suitable adhesive to cement the layers together into a rigid board. An adhesive composed of silicate andclay has advantages for cementing the layers together as hereinafter pointedout. A clay silicate mixture as described in Carter Patent No. 1,188,040, issued June 20, 1916, is suitable, but a waterproof compound, such as lime-casein glue may be used. Proper sizing of the fibers of the plies is of importance at this stage in the process,

for the sizing regulates to some extent the penetration of theadhesive and its effectiveness in producing a good bond between adv.jace'nt layers. At this laminating machine the moisture from a clay silicate adhesive, as above described,- brings the total moisture content of the board up to about 14% to 16%.

Then by kiln drying and/or by seasoning for a week or two the moisture content drops to about 12% which is the percentage preferred by me in the marketed product. A seasoned board weighs about 1000 lbs. per 1000 square I transported to a remote board mill without detrimental change in moisture content, and when cemented together into the complete board yield a product in which the moisture content is substantially uniform throughout.

The product of the present invention has good insulating qualities, more particularly because of the air pockets between the long fibers used in the outer plies. The relatively heavy pressure to which the individual plies and the individual layers have been subjected gives to the finished product greater density and flexibility than if the stock had merely been pressed lightly and thenkiln dried. The laminated form of the product contributes toward greater strength, and the clay silicate adhesive between the layers not only stifl'ens the; structure, but is to some extent a protection against fire. But most important of all the long fibered or slivered stock of the outer plies 1, 2, 3 and 4 provides the sheet with a nap or surface roughness of substantial benefit in cementing the plies together and of controlling importance on the adhesion which can be had when the board is used as a plaster-base for the inner wall of a building. "Such a plaster-base must be strong and tough, must not warp, must take up enough water to make proper bond with the plaster, and must not take up that water too ra idly. The board above described fulfills all 0 these conditions. It serves satisfactorily as the base for a plaster layer te in thickness over which may be applied a hard finish in usual manner.-

As a modificationof the preferred embodiment, I may build up a board of six la ers instead of five and I may use seven plies for each layer, instead of six thereby increasing the thickness of the board without essentiall I changing its chara teristic features. An a ditional ply in eac layer and an additional layer. in the finished board, of courses give greater strength and increased insulating power. Also, with some sacrifice in insulat-.

ing power, the plies numbered 2 and 4 of the drawings, can be made of the same material as inner plies5 and6.

--In a further modification of the invention, the outer plies l, 2, 3 and 4 consist of a mixture of ground wood screenin' s, wood flour and'fine sawdust. The wood our andsawdust may be employed in varying proportions, and I have used a mixture consisting of approximately equal parts of ground wood screenings and sawdust. The inner plies 5 and 6 may be formed from' a mixture of substantially 35% wood flour, 30% ground wood and 35% mixed paper. In preparing the stock, the above mixtures are treated in substantially the same manner as described above. In the pressing operation certain departuresjrom the usual practice are resorted to when sawdust is used inthe mixture. Normally, in the preferred embodiment of the process, I employ a machine equipped with six primary presses and three large presses. mixture from which the outer plies are formed, less pressing is desired in order to hold the density of the final product within desired limits. I accordingly employ but two primary rolls and one large roll. The weight on the primary rolls is only sufiigient to keep the machine operating, and in the/large ress I employ a light weight upper roll wit out any leverage or additional weights on it. The sheet is thus cdmpressed very little and retains practically all the bulky characteristics which the sawdust naturally imparts to it:

When sawdust-is used inthe in a lurality of plies grouped in a plural- I ity of separate layers and 'with clay silicate screenings all by dry weight and suitably sized.

4. Wall board-comprising a plurality of layers of fibrous material each consistlng of a plurality of plies, the outer plies of each layer'being composed of.wood pulp screen ings so as to provide a porous structure and a rough surface and the inner plies of'each layer for the most part being composed of short fiber pulp stock.

In testimony whereof I aflix my signature.

PIHLIP W. CODW'ISE.

A sheet is produced weighing agproxt mately 2.20 ounces per square foot an ering about .080 inches in thickness and possessing the characteristic of an extreme rough surface. The sawdust co-operates with the screenings to increase the roughness .of the surface over that which would be produced by screenings alone. This embodiment has the advantage of resulting in a five layer finished product of approximately 1 3' inch thickness.

I do not claim in this application the use of sawdust in combination with the wood pulp screenings or with ground wood screenings, this feature and these combinations bein the subject of my divisional application, No. 284,962, filed June 13, 1928, which has 1ssued as Patent No. 1,780,743, granted November 4,1930.

I claim:

calip erial .1. A laminated 'wall board having a plu f rality of plies grouped in a plurality of separate layers and with a s't-ifl'ening adhesive applied between the adjacent-layers,'eachof said layers having its outermost plies composed of course groundwood screenings of relatively long fiber length and having inner plies composed in part at least of paper waste. 2. A laminated plaster-base board comprising a plurality of'plies grouped in a plurality of separate layers with adhesive applied between adjacent layers, each of said layers having its outermost plies composed of ground'wood screenings suitably sized, and having its inner plies composed of paper waste, ground wood, and ground wood screenings all suitably sized.

3. A laminated plaster-base board compris- 

